Imagine yourself in a tropical jungle. You see a medium sized insect, about 3.5 cm long, land on a light trap. Its body is elongated, metallic black with a bluish hue, bright orange wings and long orange and black antennae. It walks around moving its antennae really fast. What could it be?
– “Dan, It’s a tarantula hawk, a wasp in the family Pompilidae, duh!”
Not so fast! In the insect world, things aren’t always what they seem, and this is a fine example:
This jaw-dropping katydid (Tettigoniidae; Phaneropterinae) belongs to the genus Aganacris, and it mimics a pompilid wasp (Pepsis are relatively common here and have very similar colors) with remarkable accuracy. Aposematic wasp mimics are common in the insect world; you can see many examples in flies (Syrphidae), moths (Sesiidae) and beetles (Cerambycidae), but seeing it in a katydid was a first. As it turns out, wasp mimicry in tettigonids is pretty rare; Nickle and Castner studied the strategies against diurnal predators used by this group in Perú, and most of the groups were leaf/bark/twig/lichen mimics; only two genera, Aganacris and Scaphura, were found to be wasp mimics. 
This is another first for me (I mentioned pentatomids making insect smoothies earlier), and I couldn’t be happier. Even though I’ve been to this particular biological station quite a few times, every time I go there I see something new and simply astonishing.
1.- David A. Nickle and James L. Castner, 1995. Strategies Utilized by Katydids (Orthoptera: Tettigoniidae) against Diurnal Predators in Rainforests of Northeastern Peru. Journal of Orthoptera Research, No. 4, pp. 75-88. http://www.jstor.org/stable/3503461